UPDATE 1-Court finds patent suit against MedImmune invalid - PDL
* U.S. court - AstraZeneca unit did not breach license deal
* Says exploring legal options, including appeal
* Shares down 7 pct pre-market
Jan 10 (Reuters) - PDL BioPharma Inc (PDLI.O) said a federal court found invalid its patent infringement claim against an antibody drug of AstraZeneca Plc's (AZN.L) (AZN.N) unit MedImmune. The district court for the Northern District of California also ruled that MedImmune did not breach a license agreement by failing to pay royalties on sales of the drug, Synagis, by its exclusive ex-U.S. distributor, Abbott Labs (ABT.N), PDL said in a statement.
The biotech company said MedImmune would, in the event it prevails on a most-favored licensee claim, request the court that PDL repay some or all of the $280 million in royalty payments already made on the drug.
PDL said it disagrees with certain aspects of the court's decisions adverse to the company and is evaluating its legal options.
The Incline Village, Nebraska-based company's shares, which have risen 6 percent since its fourth-quarter results in December, were down 7 percent at $5.75 in pre-market trade on Monday. They closed at $6.17 on Friday on Nasdaq. (Reporting by Shravya Jain in Bangalore; Editing by Unnikrishnan Nair)